Groves was nominated by President Obama in April and eventually confirmed by the Senate on 13 July.

His nomination was controversial because of concerns from some quarters that he would seek to use statistical sampling to increase counts for parts of the population which are typically undercounted – and which typically vote Democrat.

Republican senators initially blocked a vote on Groves’ confirmation, but the Democratic majority forced a vote on the matter last week. Groves has given assurances that he will play a non-partisan role.

Gary Locke, secretary of the Department of Commerce, which oversees the Census Bureau, said yesterday: “President Obama knew when he nominated Dr Groves that the job of directing the 2010 Census demanded someone with outstanding academic credentials and management skills -and as it turns out, patience. We’re depending on Bob bringing his expertise and commitment to sound science to the biggest civilian project this nation undertakes.”

Locke himself was appointed to the role of Commerce Secretary after disagreements over the census led Judd Gregg, Obama’s Republican nominee for the post, to withdraw.

Groves is not new to the Census Bureau, having served as an associate director during George Bush Sr’s presidency. He is also a former president of the American Association for Public Opinion Research and a director of the University of Michigan’s Survey Research Center.

He was sworn in in the presence of seven former Census Bureau directors and hundreds of statisticians.